Why are most galaxies/solar systems 'flat'?

"G=EMC^2 Glazier" wrote in message
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Flat because they are spinning fast and most of the galaxy's gravity is
located at its core,and its horizon. It is a pin wheel. Helps if its
flat rim is in our exact line of view. Bert


Sorry Bert,

but the rotation curves of spiral galaxies suggest this is not true. In many
spirals, the tangential velocity of stars is fairly constant with increasing
distance from the centre. If most of the mass were at the centre, the speed
would be expected to decrease with increasing distance from the centre.

Dave

"G=EMC^2 Glazier" wrote in message
...
Flat because they are spinning fast and most of the galaxy's gravity is
located at its core,and its horizon. It is a pin wheel. Helps if its
flat rim is in our exact line of view. Bert

Eh?
what does 'and its horizon' mean?

OG What I mean by horizon is its round outer edge. The edge has to be
turning faster. This would cause the galaxy to spirral out. I would like
to know if every galaxy that is flat has a bulging hub. Bert

Take a look at a pizza crust as it is being made in shops that "spins them" to
size. The spinning takes the large lump of dough and spreads it out more or
less evenly creating a larger and larger disk while all of the time its hieght
shrinks and the disk becomes flatter and thinner.

Most galaxies and solar systems are formed in a simular fashion. Those galaxies
and solar systems that are shaped diferently have had some sort of external
influence... colliding galaxies or star systems or even rogue planets passing
thru a stellar system can change the orbital paths of planets it may hit or even
pass near too.



Richard Dickison wrote:

Why are most galaxies and solar systems 'flat'? If there is a cloud of
dust/gas that starts to coalesce around a localized density in the middle of
the dust/gas, it seems it would attract from all 3 dimensions equally. But
galaxies and solar systems attract primarily in a single plane. What
happened to all the debris above/below the plane?

I understand there will probably be an unequal distribution of matter
surrounding the central object and there will consequently be a resultant
angular momentum after a while. But that doesn't seem to explain why there
still isn't debris spiraling in from above/below the primary plane.